EDIT to correct my earlier post (oops with the decimal point):
Comparing 265/45R20 to 245/60R18 with greater accuracy
As for long term odometer differences, and assuming ZERO tread wear and full tread depth can be maintained the entire 10,000 miles, the odometer on the difference would be 72.78 miles.
265/45R20 odo = 10,072.78 VS 245/60R18 odo =10,000.00
But before you condemn Honda for cheating, those calculations above are assuming that the speedometer calibration is based on 265/45R20 tires. But that is VERY unlikely because the Honda Pilot, of which the Passport is based, shares the same gauges, parts, and programming. The stock Honda Pilot of same years was equipped with 245/60R18 tires (also shared with Ridgeline) AND/OR 245/50R20 tires, which is the same tire size installed on 2019 - 2021 Passport Sport and EX-L. Those 20's have a circumference of 93.1-in, which results in 681 revolutions per mile. That is almost identical to 245/60R18 specs of 92.9 circumference, 682 revolutions per mile. So it is much more conceivable that the Passport speedo/odo is programmed to the same specs as Pilots/Ridgelines, since it would accurately cover all the higher-volume selling Pilot models, all the higher-volume selling Ridgeline models, and 2 of the 4 Passport trims.
